Malware Classification
The major malware families at a glance: behavior, propagation, and impact.
| Type | Self-replicates | Needs host | Network spread | Stealth | Primary goal |
|---|---|---|---|---|---|
| Virus | Yes | Yes | No | Medium | Infect & spread via files |
| Worm | Yes | No | Yes | Low–Med | Rapid network propagation |
| Trojan | No | No | No | Medium | Deceive user for access |
| Ransomware | Sometimes | No | Sometimes | Low | Extort money via encryption |
| Spyware | No | No | No | High | Monitor & steal data |
| Keylogger | No | No | No | High | Record keystrokes |
| Rootkit | No | No | No | Very High | Hide & maintain admin access |
| Backdoor | No | No | No | High | Provide remote access |
| Botnet | Sometimes | No | Yes | Medium | Distributed control network |
| Fileless | Sometimes | No | Sometimes | Very High | Memory-only operation |
Key categories
By spread method
- Virus: Attaches to host files. Spreads when files are shared.
- Worm: Self-replicates across networks automatically. No user action needed.
- Trojan: Disguised as legitimate software. Tricks users into installation.
By objective
- Ransomware: Encrypts files, demands payment for decryption.
- Spyware: Secretly monitors activity and steals information.
- Rootkit: Hides presence while maintaining admin-level control.
Advanced types
- Fileless: Lives only in memory (RAM). No disk footprint.
- Polymorphic: Changes its signature each infection to evade detection.
- APT malware: Sophisticated, targeted attacks for long-term access.